Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 52 for “"ferromagnetic materials"”.
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NOVEL FERROMAGNETIC MATERIALS WITH IMPROVED MECHANICAL PERFORMANCE
… investment in many of these novel magnetic materials in order to even understand, let alone correct, poor ductility.</p> <p>This dissertation includes work that explored the effect of vanadium content and quenching rate on the microstructure and ductility of Fe-Co alloys. Results indicated …
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A dynamic circuit-based model for ferromagnetic materials
… loaded SRM is typically designed to saturate the ferromagnetic material that comprises the stator and rotor of the machine whereas a lightly loaded machine does not. Therefore, the model of the machine should be able to handle both a large range in frequency and input excitation levels of the …
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Phase Field Crystal Approach to the Solidification of Ferromagnetic Materials
… formalism and including terms to incorporate the ferromagnetic phase transition and the anisotropic magneto-elastic effects, i.e., the magnetostriction effect. Using this model we performed both analytical calculations and numerical simulations to study the coupling between the magnetic and …
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Magnetic and Elastic Interactions at Cracks and Interfaces in Ferromagnetic Materials
… (phonon) interactions in piecewise homogeneous ferromagnetic spaces with two different sets of properties. The model suggests some combinations of magnetic field and frequency can produce a new kind of wave to appear. These new waves, which we call Accompanying Surface Magnetoelastic (ASM) …
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Magnetic hysteretic characterization of ferromagnetic materials with objectives towards non-destructive evaluation of material degradation
Structurele componenten en machineonderdelen vervaardigd uit staal worden vaak onder veeleisende omstandigheden uitgebaat. Dit kan aanleiding geven tot materiaaldegradatieprocessen zoals verbrossing en metaalvermoeiing. Mettertijd kunnen deze microstructurele processen leiden tot een graduele …
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An analytic solution for magnetization distribution in multigrain ferromagnetic materials in an applied magnetic field
… from grain to grain as well as the changes in ferromagnetic parameters at grain boundaries and other defect regions. For example, transmission electron microscopy results show that chromium segregation occurs at the grand boundaries in CoCrTa films, which are used in hard disk drives. In this …
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Magnetic analysis of nuclear pressure vessel steels and other ferromagnetic materials subject to neutron irradiation and heat treatment
Mechanical and magnetic property changes due to neutron irradiation and heat treatment were investigated for the sake of developing a nondestructive method of monitoring nuclear pressure vessel steel embrittlement during reactor operation. Four kinds of samples, including pressure vessel steel, …
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Nonlinear electromagnetic-thermal modeling using time domain finite element method in the machinery design
… Nonlinear magnetic problems arising from ferromagnetic materials are considered and solved by applying the Newton-Raphson method. For soft ferromagnetic materials, B-H curves are used to describe the permeability, and polynomial fitting is used to construct smooth curves from experimental …
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Spin-orbit torque switching of compensated ferrimagnetic cobalt-terbium alloys
… Recently, there has been interest in using antiferromagnetically coupled materials instead of ferromagnetic materials to store information. Compared with ferromagnetic materials, antiferromagnetically coupled systems exhibit faster dynamics and are more stable against external magnetic field …
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Electrical Manipulation of Spin Dynamics in Ferromagnetic Multi-layers
This thesis explores spin-detection in ferromagnetic materials via two different mechanisms that drive the ferromagnetic resonance – the charge-spin conversion via inverse spin-Hall effect induced by an external charge current and the photon-magnon coupling between ferromagnetic structures and …
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Development of dielectric elastomer actuators for MRI devices
… be constructed out of polymers and without any ferromagnetic materials, they can potentially be used in a Magnetic Resonance Imaging (MRI) machine, which has strict compatibility requirements that limit the use of certain materials. MRI is a powerful and effective medical diagnostic tool, but …
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Interlayer exchange coupling in magnetic multilayers
The discovery of the exchange coupling between ferromagnetic layers separated by nonmagnetic spacer layers has stimulated a great deal of interest recently. We present a theoretical study of the interlayer coupling in magnetic multilayers using two theoretical approaches. One such approach is to …
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Magnetic and thermal properties of metallic antiferromagnetic materials
Metallic antiferromagnetic materials are of great potential in spintronics due to their insensitivity to external fields and faster dynamics compared to typical ferromagnetic materials. Although they have these advantages, studies of their order parameter is difficult to perform because of the lack …
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Endoprosthetic growth module mechanism for the skeletally immature
… large extensions. They also commonly contain ferromagnetic materials which eliminate MRI imaging as a means of follow-up assessment. Thus, there is a need to develop a non-ferromagnetic device capable of carrying out frequent minor extensions comparable to natural growth. This dissertation …
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ΠΡΟΒΛΗΜΑΤΑ ΤΗΣ ΓΕΝΙΚΕΥΜΕΝΗΣ ΘΕΡΜΟΕΛΑΣΤΙΚΟΤΗΤΑΣ ΚΑΙ ΕΠΕΚΤΑΣΗ ΤΗΣ ΣΤΑ ΣΙΔΗΡΟΜΑΓΝΗΤΙΚΑ ΥΛΙΚΑ
… WELL AS THE LINEARIZED THEORY IN THE CASE OF THE FERROMAGNETIC MATERIALS, IS PRODUCED BASED ON GREENS AND LINDSAY'S AND TIERSTEN'S AND BROWN'S IDEAS.
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Pulsed field of a magnetising coil wound with a solid conductor of rectangular cross-section
… saturation fields for magnetisation of different ferromagnetic materials.
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Stress dependence of the magnetic properties of steels
… is well known that the magnetic properties of ferromagnetic materials are sensitive to microstructural and mechanical changes. Variations in applied stress, composition, and geomrtry will, either alone or in combination with each other, cause the magnetization process to change. The primary way …
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Ab initio study of magnetic effects at material interfaces .
… develop a simple, general energy functional for ferromagnetic materials based upon a local spin density extension to the Stoner theory of itinerant ferromagnetism and use it to explore the physics of grain boundaries in iron, such as interfacial energies, structures, and magnetic effects. Our …
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Development of fMRI compatible lower body negative pressure system
… system was first constructed without using any ferromagnetic materials. The LBNP system was then tested to verify its compatibility with an MRI system. Concurrently, a software program was also developed for data acquisition and analysis. Using the developed software, an electrocardiogram (ECG) …
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Development of spintronics devices and Type 1 heterojunctions from graphene nanoribbon superlattices
… the electronic structure of graphene based nanomaterials. In this work, a detailed investigation of the edge effects of graphene nanoribbon superlattices is implemented in order to guide the discovery, design, and development of novel electronic devices. Graphene nanoribbon superlattices are …
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